Intraseasonal oscillation: the global coincidence and its relationship with ENSO cycle

Based on the atmospheric reanalysis data from the National Centers for Envi ronmental Prediction / National Center for Atmospheric Research (NCEP / NCA R), the interannual variability of the atmospheric intraseasonal oscillatio n (ISO) and its relationships with the El Nino / Southern Oscillation (ENSO ) cycle have been investigated. This work reveals that there exists global coincidence in the interannual variation of ISO among different latitude ba nds and that relationships between the interannual variation of ISO and the global sea surface temperature (SST) or the outgoing longwave radiation (O LR) are very complicated. We also find that the correlation coefficient bet ween ISO and Nino3 SST anomaly has apparent decadal scale variability, whic h means that the inter-relationship is stronger in some periods and weaker in other periods.